Pyrazole-3-one derivative, method for preparing the same, and pharmaceutical composition containing the same

ABSTRACT

A pyrazole-3-one derivative of formula 1 or a non-toxic salt thereof, a preparation method thereof, and a pharmaceutical composition containing the derivative or the salt as an active ingredient are provided:                    
     wherein: 
     R 1  and R 2  each independently represent C 1 -C 3  alkyl, aryl, or substituted aryl; 
     R 3  represents amino or methyl; 
     R 4  and R 5  each independently represent hydrogen, C 1 -C 3  alkyl, halogen, methyl substituted with halogen, C 1 -C 3  alkoxy, cyano, or nitro; 
     or a non-toxic salt thereof.

This U.S. non-provisional application claims priority under 35 U.S.C.§119 to Korean Patent Application No. 2002-35411, filed on Jun. 2002, inthe Korean Intellectual Property Office, the contents of which areincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pyrazole-3-one derivative or an-toxic salt thereof, a method for preparing the same, and apharmaceutical composition containing the same as an active ingredient.

2. Description of the Related Art

Most nonsteroidal antiinflammatory agents are responsible for lockingenzyme, cyclooxygenase (COX) or prostaglandin G/H synthase, o reduceinflammation, pain, or fever. In addition, they inhibit uteruscontraction caused by hormones and also inhibit growth of severalcancers. Cyclooxygenase-1 (COX-1) was first discovered in bovine. TheCOX-1 is constitutively expressed in a variety of cell types. Unlike theCOX-1, cyclooxygenase-2 (COX-2) is a recently discovered isoform ofcyclooxygenase that can be easily induced by mitogen, endotoxin,hormone, growth factor, or cytokine.

Prostaglandin is a potent mediator for various pathological andphysiological processes. The COX-1 plays important physiological rolessuch as in the release of endogenous prostaglandin, the maintenance ofthe shape and the function of stomach, and the blood circulation in thekidney. On the other hand, the COX-2 is induced by an inflammatoryfactor, hormone, a growth factor, or cytokine. Therefore, the COX-2 isinvolved in pathological processes of prostaglandin, unlike theconstitutive COX-1. In this regard, selective inhibitors of the COX-2produce fewer and less side effects in terms of action mechanism incomparison with conventional nonsteroidal antiinflammatory agents. Inaddition, they reduce inflammation, pain, and fever and inhibit uteruscontraction caused by hormones and growth of several cancers. Inparticular, they are effective in decreasing side effects such asstomach toxicity and kidney toxicity. Still furthermore, they inhibitthe synthesis of contractile prostanoid, thereby leading to suppressionof the contraction of smooth muscles. Therefore, they help in preventingpremature birth, menstrual irregularity, asthma, and eosinophilicdisease.

Recently, it was reported that nonsteroidal antiinflammatory agents areeffective in treating large intestine cancer [European Journal ofCancer, Vol 37, p2302, 2001], prostate cancer [Urology, Vol 58, p127,2001], and dementia [Exp. Opin. Invest. Drugs, Vol 9, p671, 2000].

In addition, it is anticipated that selective inhibitors of the COX-2would be effective in treating osteoporosis and glaucoma. Utility ofselective inhibitors of the COX-2 is well described in publications[John Vane, “Towards a Better Aspirin” in Nature, Vol.367, pp215-216,1994; Bruno Battistini, Regina Botting and Y. S. Bakhle, “COX-1 andCOX-2: Toward the Development of More Selective NSAIDs” in Drug News andPerspectives, Vol.7, pp501-512, 1994; David B. Reitz and Karen Seibert,“Selective Cyclooxygenase Inhibitors” in Annual Reports in MedicinalChemistry, James A. Bristol, Editor, Vol. 30, pp179-188, 1995].

Various selective COX-2 inhibitors having different structures areknown. Among them, a selective COX-2 inhibitor having a diarylheterocyclic structure, i.e. a tricyclic structure has been widelystudied as a potent candidate. The diaryl heterocyclic structure has acentral ring and a sulfonamide or methylsulfone group attached to one ofthe aryl rings. An initial substance having such diaryl heterocyclicstructure is Dup697 [Bioorganic & Medicinal Chemistry Letters, Vol 5,p2123, 1995]. Since then, SC-58635 having a pyrazol ring (Journal ofMedicinal Chemistry, Vol 40, p1347, 1997) and MK-966 having a furanonering (WO 95/00501) were discovered as derivatives of the Dup697.

One selective COX-2 inhibitor, Celecoxib of formula 14 is disclosed inU.S. Pat. No. 5,466,823. The Celecoxib is a substituted pyrazolylbenzenesulfonamide derivative.

Another selective COX-2 inhibitor, Rofecoxib of formula 15 is disclosedin WO 95/00501. The Rofecoxib has a diaryl heterocyclic structure with acentral furanone ring.

Valdecoxib of formula 16 as another selective COX-2 inhibitor isdisclosed in U.S. Pat. No. 5,633,272. The Valdecoxib has aphenylsulfonamide moiety with a central isoxazole ring.

The selective COX-2 inhibitors of formulas 14 to 16 are effectiveinflammatory therapeutic agents with fewer and less side effects incomparison with conventional nonsteroidal antiinflammatory agents.

SUMMARY OF THE INVENTION

An aspect of the present invention provides a pyrazole-3-one derivativeof formula 1 or a non-toxic salt thereof.

Another aspect of the present invention provides a method for preparinga pyrazole-3-one derivative or a non-toxic salt thereof.

Another aspect of the present invention provides a pharmaceuticalcomposition comprising a pyrazole-3-one derivative or a non-toxic saltthereof as an active ingredient for the treatment of fever, pain, andinflammation.

Yet another aspect of the present invention provides a pharmaceuticalcomposition comprising a pyrazole-3-one derivative or a non-toxic saltthereof as an active ingredient for the treatment of cancers anddementia.

DETAILED DESCRIPTION OF THE INVENTION

According to an aspect of the present invention, there is provided apyrazole-3-one derivative represented by formula 1:

wherein:

R₁ and R₂ each independently represent C₁-C₃ alkyl, aryl, or substitutedaryl;

R₃ represents amino or methyl;

R₄ and R₅ each independently represent hydrogen, C₁-C₃ alkyl, halogen,methyl substituted with halogen, C₁-C₃ alkoxy, cyano, or nitro;

or a non-toxic salt thereof.

Preferably, the R₁ and R₂ each independently represent C₁-C₃ alkyl; R₃represents methyl; and R₄ and R₅ each independently represent hydrogen,C₁-C₃ alkyl, halogen, or C₁-C₃ alkoxy.

Preferably, the position of R₄ and R₅ is respectively 3- and 4-, 2- and4-, 3- and 5-, or 3- and 2-, and more preferably 3- and 4-.

The pyrazole-3-one derivative of formula 1 may be present in a form of anon-toxic salt. The term, “non-toxic salt” as used herein refers to apharmaceutically acceptable, toxin-free salt, including an organic saltand an inorganic salt.

The Inorganic salt of the pyrazole-3-one derivative of formula 1includes an inorganic salt of aluminum, ammonium, calcium, copper, iron,lithium, magnesium, manganese, potassium, sodium, or zinc but is notlimited thereto. Preferably, an inorganic salt of ammonium, calcium,potassium, or sodium is used.

The organic salt of the pyrazole-3-one derivative of formula 1 includesan organic amine salt of primary, secondary, or tertiary amine,substituted amine that is present in nature, or cyclic amine, or a saltof a basic ion exchange resin but is not limited thereto. Examples ofthe salt of a basic ion exchange resin include a salt of arginine,betaine, caffeine, choline, N,N-dibenzylethylenediamine, diethylamine,2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine,ethylenediamine, N-ethylmorpholine, N-ethylpyperidine,N-methylglucamine, glucamine, glucosamine, histidine, hydroamine,N-(2-hydroxyethyl)pyperidine, N-(2-hydroxyethyl)pyrrolidine,isopropylamine, lysine, methylglucamine, morpholine, piperazine,pyperidine, polyamine resin, procaine, purine, theobromine,triethylamine, trimethylamine, tripropylamine, and tromethamine.

The pyrazole-3-one derivative of formula 1 may be present in a form ofan organic acid salt or an inorganic acid salt.

Examples of the organic acid salt or the inorganic acid salt of thepyrazole-3-one derivative of formula 1 include a salt of acetic acid,adipic acid, aspartic acid, 1,5-naphthalene disulfonic acid, benzenesulfonic acid, benzoic acid, camphor sulfonic acid, citric acid,1,2-ethane disulfonic acid, ethane sulfonic acid,ethylenediaminetetraacetic acid, fumaric acid, glucoheptonic acid,gluconic acid, glutamic acid, hydroiodic acid, hydrobromic acid,hydrochloric acid, icethionic acid, lactic acid, maleic acid, malicacid, madelic acid, methane sulfonic acid, mucinic acid,2-naphthalenedisulfonic acid, nitric acid, oxalic acid, pentothenicacid, phosphoric acid, pivalric acid, propionic acid, salicylic acid,stearic acid, succinic acid, sulfuric acid, tartaric acid, p-toluenesulfonic acid, undecanoic acid, and 10-undecenoic acid. Preferably, asalt of succinic acid, hydrobromic acid, hydrochloric acid, maleic acid,methanesulfonic acid, phosphoric acid, sulfuric acid, or tartaric acidis used.

The pyrazole-3-one derivative of the present invention preferablyincludes:

5-(4-methanesulfonylphenyl)-4-(4-methoxyphenyl)-1,2-dimethyl-1,2-dihydropyrazole-3-one;

5-(4-methanesulfonylphenyl)-1,2-dimethyl4-phenyl-1,2-dihydropyrazole-3-one;

5-(4-methanesulfonylphenyl)-1,2-dimethyl-4-(4-methylphenyl)-1,2-dihydropyrazole-3-one;and

4-(3,4-dichlorophenyl)-5-(4-methanesulfonylphenyl)-1,2-dimethyl-1,2-dihydropyrazole-3-one.

According to another aspect of the present invention, there is provideda propionic acid derivative as an intermediate for the synthesis of thepyrazole-3-one derivative of formula 1, as represented by formula 4:

wherein, R₃, R_(4,) and R₅ are as defined in formula 1 and R₆ representsC₁-C₃ alkyl.

According to another aspect of the present invention, there is provideda method for preparing a pyrazole-3-one derivative of formula 1 or anon-toxic salt thereof, comprising reacting a hydrazine derivative offormula 5 with a propionic acid derivative of formula 4.

wherein, R₁ and R₂ are as defined in formula 1.

The aforementioned reactions are preferably carried out in a solventwhich can be separated from water produced during the reaction by aDean-Stark trap apparatus. Examples of the solvent include, but are notlimited to, benzene, toluene, or xylene. More preferably, toluene isused.

The reactions are preferably carried out by heating the reactant to theboiling point of the solvent and completing the reaction. Morepreferably, toluene is used as a solvent and the reactants are heated tothe boiling point of the tolene and refluxed to complete the reaction.

The separation and purification of the reaction products can beperformed by concentration or extraction, or other processes, which isconventionally used in organic synthesis process, and optionally by asilica gel column chromatography.

The said propionic acid derivative of formula 4 may be prepared byreacting a sulfonylbenzoic acid derivative of formula 2 with a phenylacetate derivative of formula 3 in the presence of a base.

wherein, R₃, R₄, and R₅ are as defined in formula 1 and R₆ representsC₁-C₃ alkyl.

The said base includes sodium hydride, potassium carbonate, or potassiumhydroxide. Preferably, sodium hydride is used.

According to another aspect of the present invention, there is provideda pharmaceutical composition comprising a therapeutically effectiveamount of a pyrazole-3-one derivative of formula 1 or a non-toxic saltthereof as an active ingredient and a pharmaceutically acceptablecarrier for the treatment of fever, pain, and inflammation.

The pharmaceutical composition comprises a compound of formula 1 or anon-toxic salt thereof when it is a selective inhibitor ofcyclooxygenase-2. Therefore, the pharmaceutical composition can be usedas an antipyretic, an analgesic, and an antiinflammatory agent, withreduced side effects.

Conventional nonsteroidal antiinflammatory agents non-selectivelyinhibit the prostaglandin synthesis enzymes, cyclooxygenase-1 andcyclooxygenase-2. Therefore, various side effects may occur.

On the other hand, a compound of formula 1 and a non-toxic salt thereofselectively inhibit cyclooxygenase-2. Therefore, the side effects ofconventional nonsteroidal antipyretics, analgesics, and antiinflammatoryagents can be reduced.

The pharmaceutical composition of the present invention comprises acompound of formula 1 and/or a non-toxic salt thereof and apharmaceutically acceptable carrier or excipient. Therefore, thepharmaceutical composition may be used as a substitute for conventionalnonsteroidal antiinflammatory agents. In particular, due to thereduction of the side effects of conventional nonsteroidal antipyretics,analgesics, and antiinflammatory agents, the pharmaceutical compositionof the present invention is useful for treating patients with pepticulcer, gastritis, regional enteritis, ulcerative colitis,diverticullitis, gastrorrhagia, or hypoprothrombinemia.

The pharmaceutical composition of the present invention can be used inall inflammatory diseases associated with pathological prostaglandin andis particularly useful in treating osteoarthritis and rheumatoidarthritis which require high dosage of nonsteroidal antiinflammatoryagents.

The pharmaceutical composition of the present invention can beadministered in form of an adult dosage of 50 mg/kg/day to 400 mg/kg/dayof the compound of formula 1. An adequate dosage is determined dependingon the degree of disease severity.

According to yet another aspect of the present invention, there isprovided a pharmaceutical composition comprising a therapeuticallyeffective amount of a pyrazole-3-one derivative of formula 1 or anon-toxic salt thereof and a pharmaceutically acceptable carrier for thetreatment of cancers and dementia.

Recently, it was reported that nonsteroidal antiinflammatory agents areeffective in the treatment of large intestine cancer [European Journalof Cancer, Vol 37, p2302, 2001], prostate cancer [Urology, Vol 58, p127,2001], and dementia [Exp. Opin. Invest. Drugs, Vol 9, p671, 2000].Therefore, it is understood that the pharmaceutical composition of thepresent invention as a nonsteroidal antiinflammatory agent can also beused for the treatment of these diseases.

The pharmaceutical composition of the present invention can beadministered in the form of an adult dosage of 50 mg/kg/day to 400mg/kg/day of the compound of formula 1 or a non-toxic salt thereof. Anadequate dosage is determined depending on the degree of diseaseseverity.

The pharmaceutical composition of the present invention may beadministered in the form of tablet, foam tablet, capsule, granule,powder, sustained-release tablet, sustained-release capsule (a singleunit formulation or a multiple unit formulation), intravenous andintramuscular injectable solution, infusion solution, suspension, orsuppository, or in other suitable dosage forms.

Sustained-release pharmaceutical dosage forms contain active ingredientswith or without an initial loading dose. They are wholly or partiallysustained-release pharmaceutical dosage forms to release activeingredients in a controlled manner.

Preferably, the pharmaceutical composition is orally administered.

The pharmaceutical composition further comprises a pharmaceuticallyacceptable excipient and/or diluent and/or adjuvant in pharmaceuticallyeffective amounts.

Examples of the excipient and adjuvant include gellatin, a natural sugarsuch as sucrose and lactose, lecitin, pectin, starch such as corn starchand amylose, cyclodextrin and cyclodextrin derivative, dextran,polyvinylpyrrolidone, polyvinyl acetate, Arabic gum, arginic acid,xylose, talc, salicylic acid, calcium hydrogen phosphate, cellulose,cellulose derivative such as methylcellulose, methoxypropyl cellulose,hydroxypropylmethyl cellulose, and hydroxypropylmethylcellulosephthalate, fatty acid having 12 to 22 carbon atoms, emulsifying agent,oil and fat, in particular, vegetable glycerol ester and polyglycerolester of saturated fatty acids, monohydric alcohol, polyhydric alcohol,polyglycol such as polyethylene glycol, aliphatic alcohol having 1 to 20carbon atoms, or aliphatic saturated or unsaturated fatty acid esterhaving 2 to 22 carbon atoms with polyhydric alcohols such as glycol,glycerol, diethylene glycol, 1,2-propylene glycol, sorbitol, andmannitol.

Other suitable adjuvants include a disintegrating agent. Examples of thedisintegrating agent include a cross-linked polyvinylpyrrolidone, sodiumcarboxymethyl starch, sodium carboxymethyl cellulose, andmicrocrystalline cellulose. A coating agent which is conventionally usedin this field may also be used. Examples of the coating agent includeacrylic acid and/or methacrylic acid and/or an ester polymer orcopolymer thereof, zein, ethyl cellulose, ethyl cellulose succinate, andShellac.

A plasticizer suitable for the coating agent is citric ester andtartaric ester, glycerol and glycerol ester, or polyethylene glycol withdifferent chain lengths.

A liquid composition such as solution and suspension is formulated inwater or a physiological acceptable organic solvent such as alcohol andaliphatic alcohol.

The liquid pharmaceutical composition may further comprise apreservative such as potassium solvate, methyl 4-hydroxybenzoate, andpropyl 4-hydroxybenzoate, an antioxidant such as ascorbic acid, and afragrant such as peppermint oil.

In addition, when the liquid pharmaceutical composition is formulated, aconventional solubilizer or emulsifier such as polyvinylpyrrolidone andpolysolvate 80 may be used.

Other examples of suitable excipients and adjuvants are disclosed in Dr.H. P. Fielder, “Lexikon der Hilfsstoffe fur Pharmazie, Kosmetik undangrenzende Gebiete” [Encyclopaedia of auxiliaries for pharmacy,cosmetics and related fields].

Hereinafter, the present invention will be described more specificallyby examples. However, the following examples are provided only forillustration and thus the present invention is not limited to or bythem.

EXAMPLE 1

3-(4-methanesulfonylphenyl)-2-(4-methoxyphenyl)-3-oxo-propionic acidethyl ester

1 g of 4-methanesulfony benzoicacid, 970 mg of 4-methoxyphenylaceticacid ethyl ester, and 950 mg of carbonyidiimidazole were dissoved in 15ml of dimethylformamide and 230 mg of sodium hydride were added dropwiseto the solution and the mixture was reacted in room temperature for 12hours. Afterwards, water was added to diute the resultant, followed byextraction with ethyl acetate. The obtained organic layer was dried overanhydrous magnesium sulfate to give 1.5 g of the title compound as alight yellow liquid(yield 83%).

¹H-NMR(400 MHz, CDCl₃) δ8.14(d, 2H, J=8.8 Hz), 8.04(d, 2H, J=8.8 Hz),6.95(d, 2H, J=8.8 Hz), 6.65(d, 2H, J=8.8 Hz), 5.11(s, 1H), 4.12(q, 2H),3.74(s, 3H), 3.10(s, 3H), 1.30(t, 3H)

1.3 g (yield 80%) of the title compound as a liquid was prepared in thesame manner as in Example 1 except using 750 mg of 4-methoxyphenylaceticacid methyl ester instead of 4-methoxyphenylacetic acid ethyl ester.

¹H-NMR(400 MHz, CDCl₃) δ8.14(d, 2H, J=8.8 Hz), 8.04(d, 2H, J=8.8 Hz),7.14(m, 5H), 5.11(s, 1H), 3.63(s, 3H), 3.09(s, 3H)

EXAMPLE 3

3-(4-methanesulfonylphenyl)-3-oxo-2-(4-methylphenyl)propionic acid ethylester

1.5 g (yield 83%) of the title compound as a liquid was prepared in thesame manner as in Example 1 except using 0.89 mg of 4-methylphenylaceticacid ethyl ester instead of 4-methoxyphenylacetic acid ethyl ester.

¹H-NMR(400 MHz, CDCl₃) δ8.14(d, 2H, J=8.8 Hz), 8.04(d, 2H, J=8.8 Hz),6.94(d, 2H, J=8.8 Hz), 6.64(d, 2H, J=8.8 Hz), 5.11(s, 1H), 4.13(q, 2H),3.10(s, 3H), 2.35(s, 3H), 1.30(t, 3H)

EXAMPLE 4

2-(3,4-dichlorophenyl)-3-(4-methanesulfonylphenyl)-3-oxo-propion aicdethyl ester

1.7 g (yield 85%) of the title compound as a liquid was prepared in thesame manner as in Example 1 except using 1.1 g of(3,4-dichlorophenyl)acetic acid ethyl ester instead of4-methoxyphenylacetic acid ethyl ester.

¹H-NMR(400 MHz, CDCl₃) δ8.14(d, 2H, J=8.8 Hz), 8.04(d, 2H, J=8.8 Hz),7.09(d, 1H, J=8.4 Hz), 7.01(s, 1H), 6.88(d, 1H, J=8.4 Hz), 5.11(s, 1H),4.13(q, 2H), 3.10(s, 3H), 1.30(t, 3H)

EXAMPLE 5

5-(4-methanesulfonylphenyl)-4-(4-methoxyphenyl)-1,2-dimethyl-1,2-dihydropyrazole-3-one

3-(4-methanesulfonylphenyl)-2-(4-methoxyphenyl)-3-oxo-propionic acidethyl ester was dissoved in 20 ml of toluene and then 0.24 g of dimethylhydrazine was added to the solution. The apparatus containing themixture was heated and refluxed at 120° C. for 24 hours in theDean-Stark trap apparatus. The reaction mixture was cooled, diluted withwater, and extracted with ethyl acetate. The obtained organic layer wasdried on anhydrous magnesium sulfate and concentrated under reducedpressure. The resultant was recrystalized with n-hexane to give 160 mgof the title compound as a yellow solid(yield 53%).

¹H-NMR(400 MHz, CDCl₃) δ8.02(d, 2H, J=8.0 Hz), 7.59(d, 2H, J=8.0 Hz),7.26(d, 2H, J=8.0 Hz), 6.83(d, 2H, J=8.0 Hz), 3.81(s, 3H), 3.51(s, 3H),3.15(s, 3H), 3.06(s, 3H)

FAB Mass(M+1):373

IR: (υC═O) 1637 cm⁻¹

Melting point: 245-247° C.

EXAMPLE 6

5-(4-methanesulfonylphenyl)-1,2-dimethyl-4-phenyl-1,2-dihydropyrazole-3-one

170 mg (yield 56%) of the title compound was prepared in the same manneras in Example 5 except using 0.3 g of3-(4-methanesulfonylphenyl)-3-oxo-2-phenylpropionic acid methyl esterinstead of3-(4-methanesulfonylphenyl)-2-(4-methoxyphenyl)-3-oxo-propionic acidethyl ester.

¹H-NMR(400 MHz, CDCl₃) δ7.98(d, 2H, J=8.0 Hz), 7.54(d, 2H, J=8.0 Hz),7.28-7.19(m, 5H), 3.47(s, 3H), 3.11(s, 3H), 3.06(s, 3H)

EI Mass(M+): 342

IR: (υC═O) 1640 cm⁻¹

Melting point: 210-212° C.

EXAMPLE 7

5-(4-methanesulfonylphenyl)-1,2-dimethyl-4-(4-methylphenyl)-1,2-dihydropyrazole-3-one

180 mg (yield 60%) of the title compound was prepared in the same manneras in Example 5 except using 0.3 g of3-(4-methanesulfonylphenyl)-3-oxo-2-(4-methylphenyl)propionic acid ethylester instead of3-(4-methanesulfonylphenyl)-2-(4-methoxyphenyl)-3-oxo-propionic acidethyl ester

¹H-NMR(400 MHz_(,) CDCl₃) δ7.99(d, 2H, J=8.0 Hz), 7.55(d, 2H, J=8.00Hz), 7.17(d, 2H, J=8.00 Hz), 7.02(d, 2H, J=8.00 Hz), 3.50(s, 3H),3.08(s, 3H) 3.05(s, 3H), 2.29(s, 3H)

EI Mass(M+):356

IR: (υC=O) 1626 cm⁻¹

Melting point: 247-249° C.

EXAMPLE 8

4-(3,4-dichlorophenyl)-5-(4-methanesulfonylphenyl)-1,2-dimethyl-1,2-dihydropyrazole-3-one

190 mg (yield 57%) of the title compound was prepared in the same manneras in Example 5 except using 0.3 g of2-(3,4-dichlorolphenyl)-3-(4-methanesulfonylphenyl)-3-oxo-propionic acidethyl ester instead of3-(4-methanesulfonylphenyl)-2-(4-methoxyphenyl)-3-oxo-propionic acidethyl ester.

¹H-NMR(400 MHz, CDCl₃) δ7.98(d, 2H, J=8.0 Hz), 7.49(d,2H,J=8.0 Hz),7.44(d, 1H, J=8.0 Hz), 7.35(s,1H), 7.07(d, 1H, J=8.0 Hz), 3.14(s, 3H),3.09(s, 3H), 3.08(s, 3H)

EI Mass(M+):411

IR: (υC=O) 1637 cm⁻¹

Melting point: 240-242° C.

Experiments 1. Evaluation of Selective COX-2 Inhibitory Activity 1)Method

In order to pharmacologically determine the selective COX-2 inhibitoryactivity, the percentages of the COX-1 and COX-2 inhibition of thecompounds of the present invention illustrated in the Examples weremeasured by the following methods.

a. Assay for the COX-1 inhibitory activity using U-937

U-937 human lymphoma cells (Korean Cell Line Bank, Seoul, Korea,Accession Number: 21593) were cultured and centrifuged. The collectedcells were diluted with HBSS (x1, Hank's balanced salt solution) to aconcentration of 1×10⁶ cells/ml. 1 ml of the dilute cell solution wasplaced into each well of 12-well plates. 5 μl of 1 μM solution of a testcompound in DMSO and 5 μl of DMSO as a control were added to the wells.The wells were incubated in CO₂ incubator at 37° C. for 15 minutes.Separately, 10 mM stock solution of arachidonic acid in ethanol wasdiluted ten times in ethanol to prepare 1 mM solution of arachidonicacid. Arachidonic acid acts as a substrate. 10 μl of the 1 mM solutionof arachidonic acid was added to each well and incubated at CO₂incubator at 37° C. for 30 minutes. The cell solution of each well wasplaced in a centrifuge test tube and centrifuged at 10,000 rpm at 4° C.for 5 minutes. The concentration of PGE2 in the collected cells and thesupernatant was quantified by means of a monoclonal kit (CaymanChemicals). The percentages of PGE2 inhibition in a group of the testcompound-treated cells in relation to a group of the DMSO-treated cellswere calculated. Based on the calculated values, the COX-1 inhibitoryactivities were evaluated.

b. Assay for the COX-2 inhibitory activity using RAW 264.7 cell line

2×10⁶ cells of RAW 264.7 cell line (Korean Cell Line Bank, Seoul, Korea,Accession Number: 40071) were inoculated into each well of 12-wellplates. Each well was treated with 250 μM of aspirin and incubated at37° C. for 2 hours. After the culture media were replaced with newculture media, the new culture media were treated with a test compound(10 nM) and incubated for 30 minutes. Then, each well was treated withinterferon (100 units/ml) and lipopolysaccharide (LPS, 100 ng/ml) andincubated for 18 hours. The culture media were transferred to other testtubes. The concentration of PGE2 was quantified by means of the EIA kit(Cayman Chemicals).

2) Test Results

The test results are presented in Table 1 below. The percentages of theCOX inhibition were calculated according to the following equation:

% Inhibition=(concentration of PGE2 in test compound-untreatedsample−concentration of PGE2 in test compound-treated sample) /(concentration of PGE2 in test compound-untreated sample)×100

TABLE 1 Cyclooxygenase (COX) Inhibition (%) Samples COX-1 (1 μM) COX-2(10 nM) Reference (Valdecoxib) 28.8 5.47 Example 5 10.5 22.5 Example 622.6 13.2 Example 7 36.5 12.5

3) Evaluation

The in vitro test results about the percentages of the COX-1 and COX-2inhibition are listed in Table 1.

As shown in Table 1, inhibition (%) ratios of COX-2 to COX-1 in Examples5 to 7 were significantly higher than that in the reference, Valdecoxib.This indicates that selective inhibition of COX-2 to COX-1 of thepresent compound is superior to that of the reference.

The compounds of Examples 5 to 7 exhibited the COX-2 inhibitoryactivities significantly higher than the reference. Based on thisresult, it can be seen that the present compounds have reduced sideeffects due to enhanced selectivity and improved relief effects offever, pain, and inflammation, compared to the reference.

As apparent from the above description, the present invention provides apyrazole-3-one derivative or a non-toxic salt thereof, a preparationmethod thereof, and a pharmaceutical composition containing thederivative or the salt as an active ingredient. The pharmaceuticalcomposition is effective in reducing fever, pain, and inflammation. Inparticular, as a result of reduction of the side effects of conventionalnonsteroidal antiinflammatory agents, the pharmaceutical composition isuseful for treating patients with peptic ulcer disease, gastritis,regional enteritis, ulcerative colitis, diverticullitis, gastrorrhagia,or hypoprothrombinemia.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

What is claimed is:
 1. A pyrazole-3-one derivative represented byformula 1:

wherein: R₁ and R₂ each independently represent C₁-C₃ alkyl, aryl, orsubstituted aryl; R₃ represents amino or methyl; R₄ and R₅ eachindependently represent hydrogen, C₁-C₃ alkyl, halogen, methylsubstituted with halogen, C₁-C₃ alkoxy, cyano, or nitro; or a non-toxicsalt thereof.
 2. The pyrazole-3-one derivative according to claim 1wherein R₁ and R₂ each independently represent C₁-C₃ alkyl; R₃represents methyl; and R₄ and R₅ each independently represent hydrogen,C₁-C₃ alkyl, halogen, or C₁-C₃ alkoxy.
 3. The pyrazole-3-one derivativeaccording to claim 1, which is selected from the group consisting of:5-(4-methanesulfonylphenyl)-4-(4-methoxyphenyl)-1,2-dimethyl-1,2-dihydropyrazole-3-one;5-(4-methanesulfonylphenyl)-1,2-dimethyl-4-phenyl-1,2-dihydropyrazole-3-one;5-(4-methanesulfonylphenyl)-1,2-dimethyl-4-(4-methylphenyl)-1,2-dihydropyrazole-3-one;and4-(3,4-dichlorophenyl)-5-(4-methanesulfonylphenyl)-1,2-dimethyl-1,2-dihydropyrazole-3-one.4. A method for preparing a pyrazole-3-one derivative of formula 1 or anon-toxic salt thereof, comprising reacting a hydrazine derivative offormula 5 with a propionic acid derivative of formula 4:

wherein: R₁ and R₂ each independently represent C₁-C₃ alkyl, aryl, orsubstituted aryl; R₃ represents amino or methyl; R₄ and R₅ eachindependently represent hydrogen, C₁-C₃ alkyl, halogen, methylsubstituted with halogen, C₁-C₃ alkoxy, cyano, or nitro; and R₆represents C₁-C₃ alkyl.
 5. The method according to claim 4, wherein thepropionic acid derivative of formula 4 is prepared by reacting asulfonylbenzoic acid derivative of formula 2 with a phenyl acetatederivative of formula 3 in the presence of a base

wherein R₃ represents amino or methyl; R₄ and R₅ each independentlyrepresent hydrogen, C₁-C₃ alkyl, halogen, methyl substituted withhalogen, C₁-C₃ alkoxy, cyano, or nitro; and R₆ represents C₁-C₃ alkyl.6. A pharmaceutical composition comprising a therapeutically effectiveamount of a pyrazole-3-one derivative or a non-toxic salt thereofaccording to claim 1 as an active ingredient and a pharmaceuticallyacceptable carrier for the treatment of fever, pain, and inflammation.7. A pharmaceutical composition comprising a therapeutically effectiveamount of a pyrazole-3-one derivative or a non-toxic salt thereofaccording to claim 1 as an active ingredient and a pharmaceuticallyacceptable carrier for the treatment of cancers.
 8. A pharmaceuticalcomposition comprising a therapeutically effective amount of apyrazole-3-one derivative or a non-toxic salt thereof according to claim1 as an active ingredient and a pharmaceutically acceptable carrier forthe treatment of dementia.
 9. A pharmaceutical composition comprising atherapeutically effective amount of a pyrazole-3-one derivative or anon-toxic salt thereof according to claim 2 as an active ingredient anda pharmaceutically acceptable carrier for the treatment of fever, pain,and inflammation.
 10. A pharmaceutical composition comprising atherapeutically effective amount of a pyrazole-3-one derivative or anon-toxic salt thereof according to claim 2 as an active ingredient anda pharmaceutically acceptable carrier for the treatment of cancers. 11.A pharmaceutical composition comprising a therapeutically effectiveamount of a pyrazole-3-one derivative or a non-toxic salt thereofaccording to claim 2 as an active ingredient and a pharmaceuticallyacceptable carrier for the treatment of dementia.
 12. A pharmaceuticalcomposition comprising a therapeutically effective amount of apyrazole-3-one derivative or a non-toxic salt thereof according to claim3 as an active ingredient and a pharmaceutically acceptable carrier forthe treatment of fever, pain, and inflammation.
 13. A pharmaceuticalcomposition comprising a therapeutically effective amount of apyrazole-3-one derivative or a non-toxic salt thereof according to claim3 as an active ingredient and a pharmaceutically acceptable carrier forthe treatment of cancers.
 14. A pharmaceutical composition comprising atherapeutically effective amount of a pyrazole-3-one derivative or anon-toxic salt thereof according to claim 3 as an active ingredient anda pharmaceutically acceptable carrier for the treatment of dementia.